In March the price is one Unicorn, but by summer you should be able to buy one for about $400-500.
If you`re willing to wait for Fermi, you should definitely wait for ATi`s next GPU in the Fall which will beat Fermi... and if you`re willing to wait for that, you should wait for Fermi2 the sequin-ing... and if you`re willing to wait that long, why not wait some more for a Genuine intel part !?!
The only thing Fermi-based part that`s a month away is their top end, and it`s not going to be anywhere in your price range, and as such will also not affect any of the prices of the cards in your range either.
There`s little in the March PR launch that will matter to you, other than to know if you should wait even longer for future cards in the fall that might possible be derivatives of the GF100.